Critical integrated circuits are tested at elevated temperatures before being installed in a product because it has been found that a vast majority of those circuits subject to failure will fail in a very short test period. These integrated circuits are frequently put in rectangular ceramic or plastic packages that have contact pads or leads, which pads or leads are electrically connected to the integrated circuit. To test the integrated circuit it is necessary to make temporary electrical connections to the contact pads or leads on the integrated circuit package. Test sockets which may be soldered to printed circuit boards having the appropriate circuitry for testing a particular integrated circuit have been provided for this purpose.
Chip carrier test sockets currently sold by Minnesota Mining and Manufacturing Company, St. Paul, Minn., the assignee of the present invention, under the Textool trademark have contact elements that make electrical contact to pads on the base of the integrated circuit package. Those sockets have covers hinged on bodies that carry the contact elements, which covers latch to the body and have a pressure pad to force the pads on the package against the contact elements. A second socket sold by Plastronics Inc. of Irving, Tex. under the trademark Lock-Nest has a top opening into which the package is inserted and contacts to make electrical connection to leads along the sides of the package. The package is released by turning the socket, and the printed circuit board to which many sockets may be soldered, upside down and pressing down on the cover of the socket to let the package fall out. A third socket, known as the NEY socket, like the Lock-Nest socket, has a top opening into which the package is inserted and contacts to make electrical connection to leads along the sides of the package. However, the NEY socket has an ejection mechanism much like in many ball point pens. The package, when inserted into the top opening, is placed on a plunger and then pressed down until the plunger locks in the depressed test position and the pressure is then released. Pressing on the package a second time releases the plunger which then moves upward carrying the package out of the socket. Each of these designs is limited in its utility since it can only be constructed to test packages with pads on their bases or packages with leads along their edges.